Adds a composer prompt on the home screen to invite users to post (#9464)

* Add a composer prompt on home

* Added image upload button

* Feed composer buttons

* Feed composer styles

* Add client events, auto-open gallery when button is pressed

* Add feature gate

* Move gate check to last

* Small style cleanups

---------

Co-authored-by: Eric Bailey <git@esb.lol>

src/view/shell/Composer.ios.tsx

@@ -45,6 +45,7 @@ export function Composer({}: {winHeight: number}) {
             text={state?.text}
             imageUris={state?.imageUris}
             videoUri={state?.videoUri}
+            openGallery={state?.openGallery}
           />
         </TooltipSheetCompatProvider>
       </View>

src/view/shell/Composer.tsx

@@ -55,6 +55,7 @@ export function Composer({winHeight}: {winHeight: number}) {
         text={state.text}
         imageUris={state.imageUris}
         videoUri={state.videoUri}
+        openGallery={state.openGallery}
       />
     </Animated.View>
   )

src/view/shell/Composer.web.tsx

@@ -110,6 +110,7 @@ function Inner({state}: {state: ComposerOpts}) {
             openEmojiPicker={onOpenPicker}
             text={state.text}
             imageUris={state.imageUris}
+            openGallery={state.openGallery}
           />
         </View>
         <EmojiPicker state={pickerState} close={onClosePicker} />